FAP and cancer: High FAP expression has been correlated to higher tumor grade, high recurrence rates, and poor survival across a wide range of human cancers, including breast [12,13,14], oral squamous cell carcinoma [15], gastric [16,17], renal [18], colorectal [19,20], lung [11,21], ovarian [22], pancreatic [23,24], and melanoma [25,26].